In the past various shipyards have devoted considerable time to the development of a slab carrying vessel having a capacity of in the order of 17,000 tonnes deadweight. The field of study was restricted to a roll-on roll-off vessel of the type described in relation to the "Iron Monarch" cargo vessel in the January, 1974 edition of "The Motorship" in pages 471 to 476 thereof, which includes extracts from a paper entitled "The design, construction and Operation of "Iron Monarch"" by R. J. Stavey and R. G. McLennan. In this type of prior art vessel a straddle carrier is utilised for collecting steel slabs from the dock and carrying it up an angled stern ramp, normally stowed in an upright position adjacent the stern of the vessel, and through a stern door to a vehicle deck in the interior of the vessel where it was transferred to bolsters which in turn were collected by overhead cranes for stowage, 6 high below the vehicle deck and 3 high above the vehicle deck, in a cellular arrangement of cargo spaces.
However, the above type of known vessel does not readily lend itself to the carriage of heavy steel slabs weighing up to 30 tonnes and not necessarily of the same cross-section or length.